Determination of Three Corticosteroids in the Biologic Matrix of Vitreous Humor by HPLC-tandem Mass Spectrometry: Method Development and Validation

Analytical Methods for the Determination of Major Drugs Used for the Treatment of COVID-19. A Review

At the beginning of the COVID-19 outbreak (end 2019 - 2020), therapeutic treatments based on approved drugs have been the fastest approaches to combat the new coronavirus pandemic. Nowadays several vaccines are available. However, the worldwide vaccination program is going to take a long time and its success will depend on the vaccine public's acceptance. Therefore, outside of vaccination, the repurposing of existing antiviral, anti-inflammatory and other types of drugs, have been considered an alternative medical strategy for the COVI-19 infection. Due to the broad clinical potential of the drugs, but also to their possible side effects, analytical methods are needed to monitor the drug concentrations in biological fluids and pharmaceutical products. This review deals with analytical methods developed in the period 2015 - July 2021 to detect potential drugs that, according to a literature survey, have been taken into consideration for the treatment of COVID-19. The drugs considered here have been selected on the basis of the number of articles published in the period January 2020-July 2021, using the combination of the keywords: COVID-19 and drugs or SARS-CoV-2 and drugs. A section is also devoted to monoclonal antibodies. Over the period considered, the analytical methods have been employed in a variety of real samples, such as body fluids (plasma, blood and urine), pharmaceutical products, environmental matrices and food.

Centrifuged-Concentrated Intravitreal Slurry Triamcinolone Acetonide: An Inexpensive, Easy, and Viable Alternative to Long-Term Steroid Delivery

Purpose:

This work reports the duration, safety, and viability of intravitreal slurry triamcinolone acetonide (TA; 1.0 mL of 40-mg/mL TA centrifuge concentrated into a 0.1-mL pellet) to treat cystoid macular edema (CME).

Methods:

A retrospective, consecutive review was conducted of patients undergoing intravitreal slurry TA injections, July 2009 to December 2018.

Results:

In 143 eyes of 120 patients, slurry TA resolved CME for a mean of 327.15 (SD = 213.11) days, or 10.76 (SD = 7.00) months, per intravitreal injection (n = 466). In 100 eyes requiring multiple injections (n = 423), mean duration was 270.95 (SD = 177.14) days, or 8.91 (SD = 5.82) months, between injections. In 43 single-injection eyes, duration was 749.30 (SD = 483.17) days, or 24.63 (SD = 15.88) months. Mean duration decreased from 337.89 (SD = 210.46) days, or 11.11 (SD = 6.92) months, in nonvitrectomized eyes to 279.74 (SD 179.63) days, or 9.20 (SD = 5.91) months, in vitrectomized eyes (n = 74 injections, t = 2.24, P = .014, 1-tailed). Central foveal thickness as shown on optical coherence tomography decreased by 173.89μ (SD = 147.56μ), from 459.16μ (SD = 47.14μ) to 285.27μ (SD = 77.27μ; t = –25.31, P < .001), within 43.41 days (SD = 36.86). Visual acuity improved from 20/100 (logMAR 0.70, SD = 0.33) to 20/74 (logMAR 0.57, SD = 0.31; SD = 0.21; t = –11.01, P < .001), within 33.98 (SD 24.98) days. Fifteen of 31 phakic eyes (48.39%) underwent cataract extraction. Fifty-seven eyes (39.86%) developed a steroid response (> 10 mm Hg increase from baseline) 94.79 days (SD = 85.52 days), or 3.11 (SD = 2.81) months, following injection.

Conclusions:

A single injection of slurry TA lasted on average 10.76 months with significant improvement of CME and visual acuity. Adverse ocular effects were comparable to currently available, long-term, implantable steroids. Slurry TA appears to be an easily reproducible, safe, and cost-effective alternative to long-term intraocular steroid delivery.

Dexamethasone delivery to the ocular posterior segment by sustained-release Laponite formulation

This paper presents a novel nanoformulation for sustained-release delivery of dexamethasone (DEX) to the ocular posterior segment using a Laponite (LAP) carrier-DEX/LAP 1:10 w w^-1 formulation; 10 mg ml^-1. In vivo ocular feasibility and pharmacokinetics after intravitreal (IV) and suprachoroidal (SC) administration in rabbit eyes are compared against IV administration of a DEX solution (1 mg ml^-1). Thirty rabbit eyes were injected with the DEX/LAP formulation (15 suprachoroid/15 intravitreous). Ophthalmological signs were monitored at day 1 and at weeks 1-4-12-24 post-administration. Three eyes per sample time point were used to quantify DEX concentration using high-performance liquid chromatography-mass spectrometry. The ocular tissues' pharmacokinetic parameters (lens, vitreous humour, choroid-retina unit and sclera) were studied. DEX/LAP was well tolerated under both administration methods. Peak intraocular DEX levels from the DEX/LAP were detected in the vitreous humour after both deliveries soon after administration. The vitreous area under the curve was significantly greater after both DEX/LAP deliveries (IV: 205 968.47; SC: 11 442.22 ng g^-1 d^-1) than after IV administration of the DEX solution (317.17 ng g^-1 d^-1). Intravitreal DEX/LAP delivery extended higher vitreous DEX levels up to week 24 (466.32 ± 311.15 ng g^-1). With SC delivery, DEX levels were detectable in the choroid-retina unit (12.04 ± 20.85 ng g^-1) and sclera (25.46 ± 44.09 ng g^-1) up to week 24. This study demonstrated the intraocular feasibility of both SC and IV administration of the DEX/LAP formulation. The LAP increased the intraocular retention time of DEX when compared with conventional solutions. DEX/LAP could be considered a biocompatible and useful sustained-release formulation for treating posterior-pole eye diseases.

Plasma concentration of metformin and dexamethasone after administration through Osseogate

BACKGROUND

Osseogate is a novel drug delivery route through bone marrow involving a modified implant used as the drug delivery system. The purpose of this study was to evaluate the effects of individual drug physicochemical characteristics on the pharmacokinetic behavior when using the Osseogate as administration route.

METHODS

Implant-mediated drug delivery systems (IMDDS) were installed in a total of 18 rabbits. After complete healing, water-soluble metformin hydrochloride was administered to one group (n = 9) while poorly soluble dexamethasone was administered to the other group (n = 9). The release patterns of each group were monitored for two weeks by measuring the plasma concentration of each drug.

RESULTS

Both groups showed relative sustained release. However, metformin hydrochloride showed more rapid diffusion and early termination of drug release compared with dexamethasone.

CONCLUSIONS

The physicochemical properties of drugs significantly affected the release pattern through Osseogate. Further research is required to achieve controlled delivery using this route.